Genealogical record keeping has traditionally involved isolated efforts to assemble and maintain stores of information about progenitors for progeny. Different cultures have created unique methods for maintaining genealogical records. Some tribes in western Africa, for example, have designated individuals who are reputed to recount by memory the names of scores of generations of ancestry and considerable additional detailed information about many individual ancestors. Most western civilizations have normally maintained written records to store such names and information, including records of births, christenings, marriages, deaths, military, civic and other governmental involvement. Much of this information is accessible on microfiche and on any of a variety of electronic media, including the Internet.
U.S. patents with application to genealogical record keeping include: U.S. Pat. No. 6,049,803 to Szalwinski “Documenting System for Entities, Attributes and Schema of a Relational Database”; U.S. Pat. No. 5,978,811 to Smiley “Information Repository System and Method for Modeling Data”; U.S. Pat. No. 5,467,471 to Bader “Maintaining Databases by means of Hierarchical Genealogical Table”; U.S. Pat. No. 5,246,374 to Boodram “Expandable Family Tree and Modular Kit for Building the Same”; U.S. Pat. No. 5,115,504 to Belove, et al. “Information Management System”; and U.S. Pat. No. 4,201,386 to Seale, et al. “Genealogy Apparatus.”
Unfortunately, the history of some people and communities has been lost or destroyed through time. In such instances, written documents are uninformative or simply do not exist. For example, descendants of slaves are often unable to locate any records of their ancestors. Illegitimacy or adoption may obstruct information or prevent access to records of biological ancestors. Similarly, immigration records may not accurately reflect the country of origin or complete surname of an individual. All of these circumstances can present significant obstacles for individuals trying to trace their “roots.” Additionally, written information relies, by its nature, on the correctness of the source. Inaccuracies in such records are rife due to limited memory, human error and purposeful efforts to conceal inconvenient or embarrassing facts.
Molecular genealogy merges the science of genetics with the study of genealogy and provides an alternative method of identifying genealogical information. By utilizing the biological genetic record that each individual retains of his/her past coded in the DNA of that individual, it is possible to reveal important clues as to his/her origin and relationship to any other person or population.
Molecular genealogy links individuals together in “family trees” based on the unique identification of genetic markers. A polymorphic genetic marker represents a specific location on a chromosome (locus) where the basic genetic units exist. A difference of a single nucleotide at a particular location on a chromosome is called a Single Nucleotide Polymorphism (“SNP”), or point mutation, and other polymorphisms are determined by the number of short tandem repeats (“STR”) of simple sequence DNA. Variant copies at any chromosomal location are termed “alleles.” Different combinations of polymorphisms on a particular chromosome can be arranged as haplotypes. The more closely related two individuals are, the more alleles they will share in common. Any two individuals may share alleles at one or a few locations. However, examination of several dozen or hundreds of chromosomal locations will uncover differences even among closely related persons. The compilation of multiple genetic markers is referred to as a genotype and serves as a unique genetic identifier for any given individual. To reconstruct molecular genealogies, it is necessary to utilize known biological relationships and correlate this information with the transmission of genetic markers through time.
Information encoded in the DNA of an individual and/or population can be used to determine the relatedness of individuals, families, tribal groups, and populations. Pedigrees based on genetic markers can reveal relationships not detectable in genealogies based only on names, written records, or oral traditions. The fact that DNA is inherited equally from both biological parents means that DNA can be used not only to create unique identifiers but also to identify members of the same family, the same clan or tribal group, or the same population.
Prior art genetic record keeping systems and methods, fueled significantly by the human genome project, identify genetic characteristics of individual members of human and other species. Some records are directed to genetic characteristics in common between and among two or more individual members of a given biological sample, irrespective of familial relation. Examples of such genetic characteristics include genes determinative of human eye, hair and skin color, height and other physical characteristics. Interspecies analyses and records have been pursued as well, such as the study of commonalities in the genetic makeup of various primates. Similar genetic characteristics may be identified among intrafamilial relations as a portion of a broader lineal genetic inheritance, such as a proclivity toward cancers, heart disease, obesity and other conditions in some family lines. An example of such intrafamilial genetic characteristics is a genetic marker for the cystic fibrosis gene discovered by Scott R. Woodward, Ph.D. et al., then of the University of Utah.
The study of any of a variety of genetic characteristics and their presence among a defined familial group has heretofore focused on medical applications within relatively few generations. Similarly, the nexus of the genealogical and genotypical disciplines finds expression only in a very limited sense in such fields as forensic science and paternity determinations, and then only for a relatively limited number of generations.
Some potential genealogical applications of genetic science are limited in their usefulness, such as the notion that all sons inherit their entire Y-chromosome from their fathers and all children inherit identical mitochondria from their mothers. For example, Y-chromosome genetic markers were analyzed in an attempt to determine whether Thomas Jefferson fathered any illegitimate children with Sally Hemings. Jefferson did not have any known direct male descendants. Therefore, a genetic sample from a known, living male relative of Jefferson's uncle was compared with genetic samples from known living male relatives of Hemings' sons. Scholars debate the conclusiveness of the test but acknowledge a likelihood that Jefferson fathered at least one son with Hemings. However, because Y-chromosome genetic markers were studied, geneticists were unable to determine whether another male relative of Jefferson fathered the children or whether any of Hemings' daughters were related to Jefferson. Similarly, geneticists could not confirm their theories by examining genetic samples from known descendants of Jefferson's daughters.
Similarly, men of Jewish descent can determine whether they are of Cohanim lineage by examination of Y-chromosome genetic markers. Such sex-chromosome investigations are limited because they involve a limited number of genetic markers and are restricted to a particular lineage and a particular sex. As females do not have a Y-chromosome and males do not pass on their mitochondrial DNA, determining whether members of the opposite sex are related can be a complicated, multi-step process.
No known method exists of combining genetic science and genealogical information to enable identification of biological ancestral relations across multiple earlier generations to a degree that is more accurate than that afforded by mere memory or written records. Thus, a need exists for a combination of genotypical and genealogical disciplines to identify chromosomal fragments that are identical by descent to elucidate family ties between siblings, parents and children, and ancestors and progeny across many generations.
A further need exists for a confluence of genetic science and genealogical resources to corroborate and improve the accuracy of genealogical data pertaining to other than strictly paternal or strictly maternal lines of ancestry.
An additional need yet exists to correlate genetic information with genealogical information to identify previously unknown biological relationships.